弯曲壁面冲击加发散冷却结构的冷却效果实验研究

Experimental Investigation on Cooling Performance of Impingement/Effusion Cooling Structures on Concave Wall

关键词:  回流燃烧室  弯曲壁面  冲击加发散冷却  压降分配  冷却效率  六边形排布

Key words:  Reverse flow combustor  Concave wall  Impingement/effusion cooling  Pressure drop distribution  Cooling effectiveness  Hexagonal arrangement

摘要:

为了研究双层壁压降分配对弯曲壁面冲击加发散冷却效果的影响，针对回流燃烧室大弯管双层壁冷却结构，保证相同当量开孔率通过调整冲击孔壁和发散孔壁的有效开孔面积之比得到了不同压降分配的冷却方案，并提出了一种六边形排布方式，选取4种冷却结构进行了冷却效果实验研究。研究表明:在相同的冷热侧进气条件下，冲击孔壁压降分配比例由19%增加至71%时，常规菱形排布结构的平均冷却效率可以提高29%，而六边形排布结构的平均冷却效率可以提高36%以上；另外，加温比对冷却效率影响较小。

Abstract:

In order to study the effects of pressure drop distribution on impingement/effusion cooling performance in the transition section of reverse flow combustor，different cooling structures with various pressure drop distribution but same equivalent orifice area were designed through adjusting the effective orifice area ratio of impingement wall to effusion wall. In addition，a novel hexagonal holes arrangement was put forward. Experimental investigation on the cooling effectiveness of four specific double-wall cooling structures was conducted under the same condition of cooling air and main flow. The results show that the higher pressure drop distribution ratio results in an extreme enhancement of cooling performance，the average cooling effectiveness of the structures punched in rhombus arrangement and hexagonal arrangement is improved by 29% and 36%，respectively，while the pressure drop distribution ratio increases from 19% to 71%. Furthermore，the temperature ratio of main flow to cooling air shows limited effect on cooling effectiveness under the condition of same mass flow flux.